The purpose of this work is to design, develop and clinically test an ultrasonic measuring device that could measure changes in the volume, dimensions and other characteristics of the human lens in vivo as a result of (a) variation in blood sugar, (b) angle closure glaucoma or (c) administration of cataract drugs. The device will be suitable for routine use in an outpatient clinic. In particular, it could be used to study the effect of aldose reductase inhibitors on the reduction of sorbitol in the lens and the resultant changes in swelling in normal and diabetic patients. The ultrasonic device will be capable of detecting small changes in ocular dimensions to within plus or minus 2.5% of the dimension measured. Dimensional characteristics will be monitored over a period of several days following modification of glucose intake or topical administration of aldose reductase inhibitors. In addition, the device could be used to monitor lens changes in angle closure glaucoma or to evaluate the effects of cataract inhibiting drugs on lens dimensions. The program will consist of: 1. The design and implementation of a clinically usable ultrasonic device capable of detecting changes in human lens dimensions to within plus or minus 2.5% of the dimensions measured. 2. Model tests to validate the accuracy of the device. 3. Selective clinical studies to test the usefulness of the device in an outpatient environment. Normal volunteers will be used to investigate changes in normal lenses. In addition, cataractous changes on volume determinations will be investigated and a pilot study will be initiated to investigate lens size changes in diabetic patients.